Process of making anthraquinone.



FRITZ SINGER AND ERN ST MILARGH,

OF orsnneecn-on-crnn-nnm, iERMANY, As-

SIGNORS TO CORPORATION OF CHEMISCHE IEABRIK GRIESHEIM'ELEKTRON, 0F

FRANKFORT-ON-THE-MAIN, GERMANY.

PROCESS OF MAKING ANTHRAQUI'NONE.

No Drawing.

To all whom it may concern I Be it known that we, Fnrrz Smcsn and lhms'rlvlimuon, both chemists and doctors of philosophy,citizens of the GermanEmpire, and residents of Offenbach-on-the Main, in the Grand Duchy ofHesse, with post-oftitxz addresses Mainstrasse 17%) and I senhurgring12,,respectively, have invented new and useful Improvements in Processesof Making Anthraquinone, of which the tol-. lowing is a pecification.

Our invention relates to a recess of transforn'iing anthracene into antiraquinone with nitric acid. t

The process consists in first treating anthracene with nitric acid at atem 'ierature under O. in presence of an indillerent liquid and in then,transtorining the intermediate product thus obtained, which is amixture of unstable n'l'eso-nitro derivatives of antl'n'acene intoantln'amiimme in presence of nitric acid at higher temperaturesthan 00As liquids can be used all 0rgenie. liquids, which resist to nitricacid, such'as forinst'ance glacial acetic acid,nit'robenzene,ehlorobcnzene. triehlorolaenzenel The process is technically veryimport-ant it being suitablenot only for pure anthracene, but also forless pure anthracene with the same success.

(lompared with the process described in .the specification ot thellritish latent No.

lltTloi 1010 the present process is distinguished b the lightregeneration oi the nitric acid, whereas the regeneration of thenitrogen-lwroxid raises objections to that process on account of thewater formed by the process of oxidation.

The lirst pr ducers of anthrmptinonc, Laurent and \nderson, have usedalso nitric acid as oxidizing agent. llut this process has never beenimportant tor technical use. because hereby a mixture of anthraquinonewith its nitro derivatives is obtained. from which anthraquinonc can beseparated with dilliculties only in a pure form (see also (iraebe andL-iebermann, Vll supplementary 'volume of ,dfltillltdit Jar tl'lzcmic,page 285).

In order to illustrate thc new process more fully. the followingexamples are given,

parts beingby weight:

Snecificattcn of, Letters Patent.

Patented July 14, 1914.

Application filed January 8, 1914. Serial in. 810,959.

i I. Eicniiple l: 117 parts of ant-hracene of 85% are suspcndet'l in 300parts of nitrobenzene. At a temperature of 20 U. Hi0 parts of nitricacid of 3191; are added,.and then the mixture is heated to (1, theimpurities, contained in technical anthracene.

are prt-iterably removed byvfiltration. and the nitric acid not used isseparated. By this'manncr 302 parts of nitric acid of 13.4 3e. areregained. The nitrobenzene solution is treated with parts of nitric acidof 48 lie. and heated to (1., until the development of red vadors, whichbegins at 50 (3., has ceased. A ter cooling down the sepa atcd crystalsof anthraquinone, are filtered, washed with nitrobenzene and benzin anddried. The anthraquinone, thus obtained. is excellently pure and meltsat 280 C. (not corrected);

Example H: parts of anthracene of 86% are suspended in 210 parts ofglacial acetic acid. At a temperature of 1520 C.

parts of nitric acid of 62% are dropped in, and then the mixture 'isstirred for two days at a tcm nwature of 15-20 C. The separated crystalsare filtered, While still wet heated in 1000 parts of nit-robenzene for4 hours to 90105 C. after addition of 17 up as described in Example I.In a very" good yield pure anthraquinone is obtained, melting at 278481(not corrected).

Now what we claim and desire to secure by Letters Patent is thefollowing:

The. process oi making anthraquinone cou-v sisting: in first treatinganthracene with nitric acid at a temperature under 00 (l. in presence otan indifferent liquid and in then lililllSfOl'lhlllQ' theintermediate'product; thus obtained into a'nlhratpiinone in presence ofnitric acid at higher temperatures than 00 C. v

In estimony, that. we claim the. foregoing as our invention, we havesigned our names in presence of two witnesses, thist-wentrthird day ofDecember 1913.

FRITZ SINGER.

. ERNST MILAR-CH.

Witnesses: i

VIKAS, S'rANn ARnT, Ersnflrrzmormparts of nitric acid of 40 B. andworkedlfle

